Automatic train-stop.



L. A. HAWKINS. AUTOMATIC TRAIN STOP. APPLICATION FILED JULY 26,1910.

1,027,047, Patented May 21, 1912 DUE] Fig: l.

7 G HillllllllllllllllllllI! C Witnesses lnvenffor Laurence AJ-lawkinsHi,s Afi'tfarney.

Tra1n-Stops, of which the following is a of rail of non-magneticmaterial, such as core, means for supplying alternating curresponsive-toa decrease in the reactance of inagnet on the locomotive or othervehicle neticcircuit of the alternating current coil change=-in= thereactance or in the terminal voltage'ofthe coil may be utilized toacturent magnet 1s instantaneous, and, second,

1,027,047. Specification of Letters Patnt- Patented May 21, 1912.Application filed July 26, 1910. Serial No. 573,908.

To all whom it may concern:

Be it known that I, LAURENCE A. HAW- KINS, a citizen of the UnitedStates, residing at Schenectady, county of Schenectady, State of NewYork, have invented certain new and useful Improvements in Automaticreference to the accompanying drawings in which- Figure 1' showsdiagrammatically a locomotive carrying a coil arranged in accordancewith my invention, the coil casing being omitted; Fig. 2 .is a diagramof circuit connections, and Fig. 3 is a somewhat diagrammatic view,partly in cross section, of lguitable apparatus for moving the magneticIn the drawings, A represents the'track rail in which is inserted ashort length of rail B of non-magnetic material, such as manganesesteel; Adjacent to this rail length 13 is placed a magnetic bar C (shownin outlines in Fig. 2) which acts as a magnetic bridge or shunt for therail length B and is movable into a position close to the head of therail length B, as shown in Fig.

3, or away from the rail head against the 7 stop 0. For moving themagnetic bar C I have indicated a small electric motor D connected tothe bar through speed reducing gearing. The bar C may be held in theposition shown in Fig. 3 by a retaining magnet E and returned to itsother positiony gravity. The bar may be partly counterweighted,asfindicated in dotted lines in Fig. 3. The motor D and retaining magnetE may be controlled by a contact f on a signal F adjacent. to the raillength B. When the signal F is cleared, the circuit is closed asindicated in Fig. 2 and the motor Ddrives the car to the position shownin Fig. 3,in which position it is held by the magnet B. When the signalF goes to stop position, the circuit of magnet E is opened and bar 0falls away from rail B by gravity.

G represents a laminated core of the horse-shoe type which is carried onthe 1000- motive with its poles as close to the rails as mechanicalconditions will permit. H represents a winding on this core which issupplied with alternating current from a small alternating currentgenerator I on the locomotive. This generator may be driven in anysuitable manner as, for in stance, from a small direct c urrentmotor Jsupplied from a small storage battery K on the locomotive.

L represents an impedance in'series with the magnet winding H.

As long as the core G is passing over the magnetic rail A, the air gapin the magnetic clrcuit is comparatively small, so that thespecification.

My invention relates to automatic train stops for use in connection withblock signal systems, and particularly to that type of system in whichthe magnetic continuity of the'rails is interrupted at certain pointsas, for instance, by the insertion of a length manganese steel, and inwhich means is provided for magnetically bridging the spaces whichproducethis continuity.

y invention consists in providing a mag netic core carried on a vehiclewith its poles adjacent to the track rails, a (3011 on the rent to thecoil, and a device on the vehicle the coil. When the alternating currentis passing over the magnetic running rails, its magnetic circuit isnearly closed, so that the-reactance of the winding of the magnet ishigh: In passing over the non-magnetic rail lengths if these lengths arenot magnet-ica-lly bridged, the reluctance of the mag- '18 very greatlyincreased and its reactance is, therefore, greatly diminished. This atea device on the locomotive for giving a warning i'ndication or forapplying the brakes. -I :he advantages of using such an alternatingcurrent magnet are, first, that very quick action is obtained, since thechange in reactance of the alternating curthat, sincethsignaling orbrake controlling device andall movingparts may be placed in thelocomotive cab, where they are well protected from injury and areconveniently accessible for inspection, the coil itself, which is theonly part of the apparatus which is carried near the rails and isexposed to the weather, having no moving parts and, consequently,requirmg no inspection, may be placed in a well sealed casing.

My invention will best be understood byy will ticular construction meansfor magnetically cuited, notice will at once reaetance of winding His'high. -When the core passes over he non-magnetic rail length B, ifthe signal F is clear and the magnetic bar C iscclose to the head ofrail B, the reluctance of the magnetic circuit 0 coil II will not begreatly changed, but if bar G is in its other position the air gap inthe magnetic circuit ofwinding H will be very greatly increased, so thatits reactance will be greatly diminished. A greater current would thentend to flow, but the impedance L, is made high enough so that thecurrent is not greatly increased. The net result is to decrease theterminalvoltage of winding H- and the flux in ,core' G. If a magnet M isconnected in" shunt towinding H the voltage on the terminals of thismagnet will be very greatly reduced, if the locomotive passes over therail length B with signal 1* at stop. Under these conditions magnet Mwill release its armature m, which in turn releases a valve N which isthen moved by a spring so as to open the train pipe 0 to atmosphere andapply the brake. A resetting handle n may be provided on the valve.

\Vith the arrangement above described, a quick and positive applicationof the brakes be obtained whenever an attempt is made to pass a signalin stop'position. The coil'I-I. and its core-may beincased so as to bewell protected from the weather, since no inspection of this coil isrequired: This casingisnotShown in'th'e drawings. If the coil shouldbecomein any manner short-cirbe given by the magnet m. which willrelease its armature and apply the brake. Furthermore, if the voltage ofthe terminal I should fail, for any cause, or the circuit of thegenerator should be opened, the magnet M will also give an indication.The bar C. and its actuating mechanism may also be well inclosed fromthe weather. The casing both for this bar and fort-he magnet .H shouldbe of non-i'nagnetic material such, forinstance, as manganese sheetsteel.

I do not desire tolimit myself to the parand arrangement 0 parts shownand described, but aim in the appended claims to cover all modificationswhich are within the spirit. and scope of my invention. i

- \Vhat I claim as new and=desire to secure by Letters Patent of theUnited States, is

1. In combination with the track rails of a railway, non-magneticspacesin said rails,

bridging the non- Gopies of this patentmay be obtained'for coil on saidcore, means magnetic spaces, a magnetic vcore having an open magneticcircuit carried on a vehicle with its poles adjacent to the track rail,a coil on said core, means for supplyingalternating current to saidcoil, and a device on said vehicle responsive to a decrease in thereactanoe of said coil.

2. In combination with the track rails of a railway, non-magnetic spacesin said rails, means for magnetically bridging. the none magneticspaces, a magnetic core having an open magnetic circuit carried on avehicle with its poles adjacent to the track rail, a

for supplying alternating current to said coil, and a device on saidvehicle responsive toa drop in the terminalvoltage of said coil. I e I I3. In con bination with the trackrails of a railway, non-magnetic spacesin said rails, means for magnetically bridging the nonmagnetic spaces,'a magnetic core having an open magnetic circuit carried on a vehiclewith its poles adjacent to the track rail, a coil on said core, meansfor supplying alter.- nating current to said coil, a device on saidvehicle responsive to adecrease in the re actance of said coil, andspeed-controlling means on said vehicle controlled by said device.

4. In combination wit-h the track rails of a railway, non-magneticspacesin said rails, means for magnetically bridging the non: magneticspaces, a magnetic core having an open magnetic circuit carried on avehicle with its poles adjacent to thetrack rail, a coil on said core, asource of alternating current on said vehicle connected to said coil, animpedance device in series with said coil, and. a magnet winding inshunt to' said coil.

5. In a railway, non-magnetic means for magnetically magnetic spaces, amagneticcore having an open magnetic circuit carried on a vehicle withits poles adjacent to the track rail, a coil on said core, a source ofalternating current on said vehicle connected .to said coil, animpedance device in series with said coil, a magnet winding, andconnectionsfor impressing on 7 age varying directly as the flux in saidcore.

In witness whereof, I have my hand this 25th day. of July, 1910.

LAURENCE A. HAWKINS.

Witnesses:

BENJAMIN B. I-IULL,

HELEN Onronn.

spaces in said rails,

five cents each, by addressing the Commissioner of Iatents. Washington,D. C.

bridg ng the non- I hereunto set i

